The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John:
2 Who bare record of the word of God, and of the testimony of Jesus Christ, and of all things that he saw.
3 Blessed is he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand.
Actually the opposite of your contention is true. If most of the book is still to come, then it wouldn't have made any sense at all to the 1st century audience, for whom it was mainly written. The book is nearly all symbolic.
When read with the intended 1st century readers in mind, and understanding the intended symbolism, Revelation is a wonderful book.
Care to explain exactly when and how the events in Revelation occured during the first century?